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Idiopathic anaphylaxis

2/23/2013
For the past several years, I have seen, and have been consulted in hospitals for, cases of localized angioedemas, anaphylaxes, and urticarias. So far all of them had normal labs. for CH50, C2, C4, C'1INH.,tryptase, CBCs, and alpha-gals. Skin tests for foods have been negative as well in some relevant cases. I know that, in the absence of serious systemic signs, malignancy will be out of the question.

Last month, one 18 year old Caucasian girl was seen by another allergist, for recurrent angioedemas and anaphylaxes, unrelated to any foods she knew of. Her ANA, complements, liver enzymes, ESR, C'1 INH, and CBC were normal, as ordered by that allergist. She came and saw me, for a second opinion, and I ordered serum tryptase and alpha-gal, which were normal, as well. Her mother was concerned that the other allergist raised a slim possibility of a small percentage of lymphoma and ordered many imaging studies, and which was why I saw her. That allergist also urged her to seek an opinion at Mayo and I recommended postponing it, since she was otherwise doing very well, physically. I have not done food skin tests yet, since her last reaction was less than 3 weeks ago.

A second case was a 70 year old Caucasian man with a few visits to the ER for apparently idiopathic anaphylaxes, since 2002. In his last visit he had an elevated serum tryptase of 20, and I repeated it. It came down to 2, and the tryptase as well as alpha-gal were normal. Skin tests in 2002 for common foods were negative. His physical exams have been otherwise unremarkable, except that he still is an obese man to this date.

Do you have different takes on these 2 cases, after your perusal? I will really appreciate scholarly and authoritative opinions on these subjects. Than you very much in advance.

A:

Thank you for your inquiry.

We have dealt with numerous questions, over the years, regarding recurrent idiopathic angioedema, idiopathic urticaria, and anaphylaxis. It is important to note that these three should be considered, at least in the vast majority of cases, different entities. That is, they are not usually quantitatively different, but qualitatively different. The workup for each would also differ. I mention this because you cited in your inquiry that you have dealt with patients of all three varieties, as all allergists do, and also mentioned that the 18 year old girl was seen for “recurrent angioedema and anaphylaxis.” In looking at the evaluation of this patient, it appears that many of the tests ordered would not be expected to be helpful, and not every test ordered for any one of the three conditions would be considered helpful for the other two.

I also mention this general observation because you did not ask for an answer to a specific question, but rather “our take” on these cases.

My take on both is that they will probably remain idiopathic in nature no matter what studies are performed. Also, it should be noted that the vast majority of cases of all three of these entities are not related to any life-threatening condition such as a lymphoma. In the brief history that you gave us, I would not have considered her at any significant risk for any systemic disease of a threatening nature to including any neoplasm.

In the case of the 70 year old, the one discerning feature is the elevated tryptase if you did obtain it during an asymptomatic phase. Tryptase, like all laboratory tests, are subject to error, and obviously, if both of these tests were obtained in an asymptomatic phase, one is an error. The importance of delineating whether or not the patient did have an elevated tryptase during an asymptomatic phase is that, if so, a bone marrow might be considered to rule out systemic mastocytosis or a mast cell-activating disorder. So, since you have not clarified the issue of whether or not the tryptase was abnormal, a third test might be considered.

In summary, more than likely both of these cases will remain idiopathic in nature, and it is unlikely that either is associated with any threatening disease.

As noted, we have many entries on our website that discuss idiopathic anaphylaxis, idiopathic angioedema and urticaria. These deal with management and also cite review articles that may be of help to you. You can access these entries by going to the Ask the Expert website and typing the following into the search box:
1. Idiopathic anaphylaxis
2. Recurrent angioedema
3. Idiopathic angioedema
4. Urticaria

Thank you again for your inquiry and we hope this response is helpful to you.